Charge pumps (CP) are used in many applications to provide higher voltages than a supply voltage. In other words, such charge pumps make it possible to output a higher output voltage based on a lower input voltage. In many charge pump designs, switching transistors are controlled in such a way that a capacitor is charged and discharged periodically. In such designs, the charge pump may generate electromagnetic interference that is caused by currents switching.
In many applications, the switched currents are converted to direct currents in order to reduce such electromagnetic interference and emissions. One or more constant current sources are conventionally used for this purpose. In conventional implementations, the implementation of these constant current sources requires a comparatively large chip surface area in order to limit heating on account of high power losses.
It is an object of the present invention to provide possibilities for implementing such charge pump circuits with a smaller chip surface area.